Method of producing a road wheel for a track vehicle

Abstract

A road wheel for a track laying vehicle is made by initially roll pressing and projection drawing a planar disk of temperable steel into a blank having a cylindrical portion, a planar hub portion and an intermediate portion bridging the hub and peripheral projection. Prior to machining at least of the intermediate portions, the blank is tempered and thereby increased in size. The blank is reshaped following the tempering and prior to machining to the original blank shape and is then machined.

We claim:  
     
       1. A method of making a road wheel for a track-laying vehicle, comprising the steps of: 
       (a) shaping by roll pressing and projection drawing a planar disk of steel to a rotationally symmetrical dished wheel blank for said road wheel and having an inner hub portion, an outer peripheral portion and an intermediate portion bridging said hub portion and said outer peripheral portion;  
       (b) prior to machining of said inner hub portion and said outer peripheral portion, quenching and tempering said blank and thereby increasing a size of said blank;  
       (c) subsequent to quenching and tempering of said blank and prior to machining of said inner hub portion and said outer peripheral portion reshaping said blank by roll pressing and projection drawing to an original size of said blank; and  
       (d) thereafter machining said inner hub portion and said outer peripheral portion to a final shape.  
     
     
       2. The method defined in  claim 1  wherein the reshaping of said blank in step (c) is carried out on an inner tool identical to or of the same shape as an inner tool used for shaping in step (a). 
     
     
       3. The method defined in  claim 1  wherein said disk is composed of a heat treatable steel containing at least 1% by weight chromium and at least 0.2% by weight molybdenum. 
     
     
       4. The method defined in  claim 1  wherein the blank is quenched and tempered in step (b) to a strength of 1150 to 1250 N mm −2 . 
     
     
       5. The method defined in  claim 1  wherein the blank is quenched and tempered in step (b) in a salt bath. 
     
     
       6. The method defined in  claim 1  wherein the blank is quenched and tempered in step (b) in a vacuum furnace.